This invention relates to franking machines and in particular relates to controlling use of such machines.
Franking machines are utilised to frank items of mail by printing on the mail item a franking impression indicating that a postage charge for the item has been accounted for. Often franking machines operate in a pre-payment mode in which a value of credit is stored in a register of the franking machine and as a part of each operation to frank an item, the credit value is decremented by an amount equal to a postage charge for the item. Other registers of the franking machines are usually provided to maintain for example a total value of postage charge dispensed by the franking machine, the number of items franked and the number of items franked with a postage charge greater than a predetermined value.
When permitted by a postal authority, franking machines may be operated in a post-payment mode. In a post payment mode of operation the franking machine maintains an account of postage value used in franking mail items with postage charges and periodically the accounting data in the registers of the franking machine is provided to the postal authority and the user is billed in accordance with the accounting data for postage value used in the preceding time period. In order to ensure that the postal authority receives payments at substantially regular intervals for postage value used, the franking machine may be caused to lock at predetermined time periods or upon completion of a predetermined number of franking cycles.
Use of a franking machine by a user is licensed by the appropriate postal authority under conditions determined by the postal authority. These conditions usually include inter alia that the franking machine will be used only at a specifically authorised location. However since franking machines are relatively small machines they are relatively easily transported and may be removed from the authorised location to be used at another unauthorised location where attempts may be made to operate the franking machine in a fraudulent manner.